UPDATEBob Mackie has opened up about not designing the costumes for Cher's latest tour. The legendary designer tells Us Weekly, "Nobody wanted to design this last tour more than I did! I am sick about it. My professional and business commitments were just too great. There simply was not enough time to give this wonderful project the proper amount of care and attention it deserves. After all these years of collaborating, it is like turning down your own little sister, and how many guys have a little sister like Cher."

If only they could turn back time!

Cher and longtime designer Bob Mackie are on the outs. The "Believe" singer tweeted her disappointment that Mackie, who is known for his flamboyant styles, feathers, and beads, couldn't design the costumes for her Dressed to Kill tour, which kicks off on March 22 in Phoenix.

"Telling you something t that has broken my heart," Cher tweeted on March 13. "The man who made all my costumes since 1972 decided he couldn't do my last tour."

The split of the dynamic duo was apparently not an amicable one. "No matter how disappointed any of u are, you don't know my grief," Cher, 67, tweeted. "I'm sure Bob can't know how much I miss him. Felt I had to tell u I'm crying."

She also explained that she pleaded with Mackie, 73, to squeeze her in to his apparently busy schedule. "I tried to convince him to end with me, but he had many reasons as 2 why he couldn't do it. 2 many obligations not enough time even 2 do 1."

However, all hope is not lost: Cher has teamed up with another designer for her tour. "Thank god I have a lovely man & wonderful designer!! Hugh Durant," Cher tweeted. "He is talented & brave. We will persevere."

Cher and Mackie first met when he worked on The Carol Burnett Show. "It was 1967 and I was working on a loose thread on a beaded gown and Cher came over and said, 'Oh, someday I'm going to have one of those," Mackie said (via WWD). "And we became friends after that."

Cher and Bob Mackie attend the Diana Vreeland costume exhibit at the Metropolitan Museum in New York City in 1985Credit: Ron Galella/WireImage.com

Mackie then exclusively worked with Cher during the four years of The Sonny & Cher Comedy Hour beginning in 1971. "It's not like dressing a regular person; it's like dressing a crazy goddess," Mackie has said. "Sometimes she's an Egyptian goddess, and sometimes she's a biker chic goddess."

In August 2013, it was reported that Mackie and Cher would partner for her latest round of farewell concerts. He was expected to make around 20 costumes. "When you change that many times, you don't wear any one thing for very long," Mackie said. "And it's not a big dancing operation here."